JP7238467B2 - Image forming apparatus, image forming method, and program - Google Patents

Description

The present disclosure relates to an image forming apparatus, an image forming method, and a program that receive an interrupt request for another image forming job during execution of another image forming job.

Conventionally, there have been proposed various techniques related to an image forming apparatus that accepts an interrupt request for an image forming job while the image forming job is being executed. For example, the image forming apparatus described in Japanese Patent Application Laid-Open No. 2002-200000 temporarily interrupts the copy operation being executed when an interrupt copy button is pressed during copying in a state where the double-sided copy mode is selected, and interrupts the copy operation. Start working.

JP 2003-186355 A (especially paragraph 0012)

By the way, the image forming apparatus disclosed in Patent Document 1 accepts an interrupt request for another image forming job while executing an image forming job for forming images on both sides of a sheet. When receiving an interrupt request for another image forming job in this way, the image forming apparatus discharges all the sheets being conveyed to the outside of the apparatus, interrupts the processing related to the image forming job being executed, start the interrupt processing related to the image forming job. Therefore, there is a possibility that the start of image formation related to other image formation jobs will be delayed.

Accordingly, the present disclosure provides an image forming apparatus, an image forming method, and an image forming apparatus that can expedite the start of image formation related to an interrupt image forming job when an interrupt image forming job is requested during image formation on both sides of a sheet. and to provide programs.

In order to achieve the above object, the present application provides a discharge tray, an image forming/conveying section for conveying a sheet to an image forming position, a discharging/conveying section for discharging a sheet that has passed the image forming position to the discharge tray, and the image forming apparatus. a conveying unit for reconveying a sheet reversed after passing a forming position to the image forming position; an image forming unit for forming an image on the sheet conveyed to the image forming position; and a control unit. and, when receiving a double-sided image forming job, the control unit controls the conveying unit and the image forming unit to form images on the first surfaces of each of the plurality of sheets, and The image forming apparatus executes double-sided image forming processing in which processing for forming an image on the second surface of each of the sheets is set as one cycle, and the control unit controls the double-sided image forming process. interruption processing for controlling the image forming unit and interrupting the operation of the image forming unit relating to the double-sided image forming process when an interrupt image forming job is received during execution of the forming process; a retention process of controlling the transport unit to retain the sheet existing in the transport unit in the re-transport unit; and an interrupt image forming process for forming an image related to the interrupt image forming job on a sheet by controlling the image forming apparatus.
Further, the contents disclosed in the present application can be implemented not only as an image forming apparatus, but also as an image forming method in an image forming apparatus and a program executed by a computer that controls the image forming apparatus.

According to the image forming apparatus and the like of the present application, the conveying section has a re-conveying section for conveying the reversed sheet, in addition to the discharge conveying section for discharging the sheet on which image formation has been completed. Therefore, by allowing the sheets of the previous double-sided image forming process to stay in the re-conveying section, it is possible to eliminate the sheets in the image forming conveying section and the discharge conveying section. The control unit can start an interrupt image forming job and start forming an image on a new sheet in a state in which the sheet on which the image is being formed is held in the conveying unit. Therefore, when an interrupt request for a new image forming job is made during double-sided image forming processing for both sides of a sheet, it is possible to advance the start of image forming related to the interrupting image forming job.

2 is a central cross-sectional view showing the internal configuration of the MFP according to the embodiment; FIG. 3 is a block diagram showing the control configuration of the multifunction machine; FIG. It is a figure which shows the display screen of the touch panel which receives interrupt processing. FIG. 10 is a diagram showing the state of three sheets arranged in the conveying unit during printing according to the 246135 method; 4 is a flow chart showing the contents of interrupt control; 4 is a flow chart showing the contents of interrupt control; FIG. 10 is a diagram showing a state in which two pages are printed on the back side of the first sheet; FIG. 10 is a diagram showing a state in which the first sheet is carried into the switchback conveying section; FIG. 10 is a diagram illustrating a state in which a sheet on which the last page (N−1) is printed is carried into the reversing conveying unit; FIG. 10 is a diagram illustrating a state in which switchback is performed in the discharge conveying portion while sheets are retained in the switchback conveying portion; FIG. 10 is a diagram showing a state in which 4 pages are printed on the back side of the second sheet; FIG. 10 is a diagram showing a state in which the preceding sheet is retained in the reverse conveying portion and the succeeding sheet is retained in the switchback conveying portion; FIG. 13 is a diagram showing a state in which 6 pages are printed on the back side of the third sheet in accordance with the 246135 method; FIG. 12 is a diagram showing a state in which one page is printed on the front surface of the first sheet in accordance with the 246135 method;

(1. Configuration of MFP)
Hereinafter, one embodiment of the present application will be described in detail based on the drawings. FIG. 1 schematically shows a central section showing the internal configuration of a multifunction device 1 of this embodiment. The multifunction device 1 is a color laser type multifunction device, and has a copy function, a printer function, a scanner function, a facsimile function, and the like. In order to mainly explain the printer function of the MFP 1 in this embodiment, FIG. 1 shows the configuration of the image forming section 3 in detail. When referring to directions in the description using FIG. 1, the directional arrows shown in the same figure are used as a reference.

As shown in FIG. 1, the multifunction machine 1 has a transport section 20 that transports a sheet P (paper, OHP sheet, etc.). The transport section 20 has an image forming transport section 4, a discharge transport section 5, a switchback transport section 12A, and a reverse transport section 12B. Details of each transport unit will be described later.

The multi-function device 1 includes a housing 2 having a paper discharge port 2A, an image forming section 3, an image forming/conveying section 4 having an image forming path 4A, and a discharge/conveying section 5 having a discharge path 5A. The housing 2 constitutes the exterior of the multifunction device 1 and has a box shape. The housing 2 accommodates the image forming section 3, the image forming conveying section 4, the discharge conveying section 5, and the like.

Further, an image reading section 13 is provided on the upper portion of the housing 2 . The image reading unit 13 includes an image sensor such as a CIS (Contact Image Sensor) or a CCD (Charge-Coupled Device). The image reading unit 13 moves the CIS or the like with respect to the document placed on the document table, reads the document, and generates image data.

A discharge tray 2B is provided on the upper surface of the housing 2 . The discharge tray 2B has an inclined surface that slopes downward from the front toward the rear. The discharge port 2A is arranged behind and above the discharge tray 2B. A hole penetrating the housing 2 in the front-rear direction is formed in the paper exit 2A. The discharge port 2A communicates the inside and outside of the housing 2 with each other.

The image forming section 3 is arranged in the center of the multifunction machine 1 . The image forming unit 3 includes a plurality of (four in this embodiment) photosensitive drums 6, a plurality of (four in this embodiment) developing devices 7, an exposure device 8, a transfer unit 9, and a fixing device 10. . The image forming section 3 prints on the sheet P supplied from the image forming/conveying section 4 by electrophotography under the control of the control section 61 (see FIG. 2) of the multifunction machine 1 . The four photosensitive drums 6 are arranged with a space therebetween in the front-rear direction. Each photosensitive drum 6 has a cylindrical shape extending in the left-right direction. The four developing devices 7 are arranged with a space therebetween in the front-rear direction. Each developing device 7 is arranged above and in front of the photosensitive drum 6 and contains toner.

Each developing device 7 also includes a developing roller 7A. Each developing roller 7</b>A is arranged at the rear lower end portion of the corresponding developing device 7 . Each developing roller 7</b>A contacts the corresponding photosensitive drum 6 and supplies toner to each photosensitive drum 6 . The exposure device 8 is arranged above the four developing devices 7 and emits laser light L based on image data. Each of the four laser beams L emitted from the exposure device 8 passes behind each developing device 7 and strikes the surface of each photosensitive drum 6 .

The transfer unit 9 is provided below the four photosensitive drums 6 and arranged along the front-rear direction. The transfer unit 9 includes a belt 9A and a plurality (four in this embodiment) of transfer rollers 9B. The belt 9A is an endless belt, and contacts the four photosensitive drums 6 on its upper surface. The belt 9A is rotatable so as to move the upper surface from front to back. The four transfer rollers 9B are arranged with a space therebetween in the front-rear direction. Each transfer roller 9B is arranged below the corresponding photosensitive drum 6 and sandwiches the belt 9A between the transfer roller 9B and the photosensitive drum 6 .

The fixing device 10 is arranged behind the transfer unit 9 and has a heating roller 10A and a pressure roller 10B. The heating roller 10A has a heat source such as a halogen lamp and is rotatably provided. The pressure roller 10B is arranged below the heating roller 10A and is in contact with the heating roller 10A so as to press it. A branch sensor 50 is provided at the outlet of the fixing device 10 . In the multifunction machine 1 of the present embodiment, a plurality of sheet sensors (a paper feed sensor 51, a paper discharge sensor 52, a reversing path sensor 53, etc., which will be described later) including the branch sensor 50 are provided in the transport section 20 for transporting the sheet P. ing. These sheet sensors (such as the branch sensor 50) are optical sensors, for example, and have detection areas set on the conveying section 20. (See FIG. 2) Output.

A plurality of paper discharge rollers 15 are provided in the discharge path 5</b>A of the discharge transport section 5 . A plurality of motors M are provided behind the paper feed tray 11 in the housing 2 of the present embodiment. The output shaft of the motor M is drivingly connected to the discharge roller 15 . The discharge roller 15 is rotated by the driving force of the motor M to convey the sheet P. As shown in FIG. The branch sensor 50 is provided between the fixing device 10 and the discharge roller 15 provided behind the fixing device 10 . The control unit 61 can detect the sheet P discharged from the fixing device 10 to the discharge rollers 15 based on the detection signal of the branch sensor 50 .

The image forming/conveying section 4 is arranged below the multifunction machine 1 and conveys the sheet P to the image forming section 3 . The image forming/conveying unit 4 includes a paper feed tray 11, an image forming path 4A, a paper feed roller 16, a paper feed sensor 51, and the like. The paper feed tray 11 is arranged below the transfer unit 9 and accommodates the sheets P therein. The image forming path 4A extends forward and upward from above the front end portion of the paper feed tray 11, curves rearward, and extends to the position of the frontmost photosensitive drum 6 (an example of an image forming position). A plurality of paper feed rollers 16 are provided in the image forming path 4A. The paper feed roller 16 is rotated by the driving force of the motor M to convey the sheet P. As shown in FIG. The motor M for driving the paper discharge roller 15 and the motor M for driving the paper feed roller 16 may be the same motor M or may be different motors. A paper feed sensor 51 is provided in the image forming path 4A. The paper feed sensor 51 includes a paper feed roller 16 provided at the front end of the paper feed tray 11 and a paper feed roller provided at a position downstream of the paper feed roller 16 at the front end of the image forming path 4A. 16 and between the two paper feed rollers 16 . Based on the detection signal from the paper feed sensor 51, the controller 61 can detect that the sheet P has been conveyed from the paper feed tray 11 into the image forming path 4A.

The ejection transport section 5 is provided at the rear upper end portion of the multifunction machine 1, and ejects the sheet P that has passed through the fixing device 10 to the ejection tray 2B. The ejection transport section 5 includes an ejection path 5A, an ejection roller 15, an ejection sensor 52, and the like. The ejection path 5A extends upward from behind the fixing device 10, curves forward, and communicates with the paper ejection port 2A. A discharge sensor 52 is provided in the discharge path 5A. The paper ejection sensor 52 is arranged near the paper ejection port 2A. Based on the detection signal of the sheet ejection sensor 52, the control section 61 detects that the sheet P has been ejected to the ejection tray 2B.

Next, a configuration for re-conveying the paper will be described. As shown in FIG. 1 , the multifunction machine 1 includes a re-conveying section 12 , a flap 31 , a guide section 35 and two stack levers 41 . Further, the housing 2 has a passage opening 2C. The passage opening 2</b>C is arranged at the rear upper end portion of the housing 2 . A hole penetrating the housing 2 in the front-rear direction is formed in the passage port 2C. The passage port 2</b>C communicates the inside and the outside of the housing 2 . The passage port 2C is arranged behind and above the paper discharge port 2A. That is, the passage port 2C is arranged above the paper discharge port 2A in the vertical direction, and is arranged behind the paper discharge port 2A in the front-rear direction.

The two stack levers 41 are provided above the paper ejection port 2A and are rotatable about a rotation axis extending in the left-right direction. The multifunction machine 1 has a drive source (eg, solenoid) that changes the rotational position of the stack lever 41 . The control unit 61 changes the rotational position of the stack lever 41 by controlling the drive source. The stack lever 41 is rotated upward by the sheets P stacked on the discharge tray 2B. The stack lever 41 suppresses the positional deviation of the sheets P on the discharge tray 2B by holding down the stacked sheets P from above. Also, the stack lever 41 rotates to the position indicated by the solid line in FIG. The rib 44 of the stack lever 41 extends forward along the rib 35A of the guide portion 35, which will be described later.

The re-conveying section 12 includes a switchback conveying section 12A and a reversing conveying section 12B. The re-conveying section 12 is arranged at the rear end and the lower end of the multifunction machine 1 and conveys the sheet P that has passed through the fixing device 10 to the image forming and conveying section 4 . The switchback transport section 12A is arranged behind the discharge transport section 5 . The transport path of the switchback transport section 12A extends rearward and upward from the exit of the fixing device 10, passes under the flap 31, curves upward, and then curves forward and upward like the discharge transport section 5. and communicates with the passage port 2C. Therefore, the conveying section 20 of the multifunction machine 1 branches behind the fixing device 10 into the discharge conveying section 5 and the switchback conveying section 12A. A plurality of reversing rollers 17 are provided in the switchback conveying section 12A. The plurality of reversing rollers 17 are rotated by the driving force of the motor M. As shown in FIG. The plurality of reversing rollers 17 can be switched between a first rotation direction for conveying the sheet P upward and a second rotation direction opposite to the first rotation direction for conveying the sheet P downward. is.

The transport path of the reversing transport section 12B curves forward from below the flap 31, then extends forward below the paper feed tray 11, curves upward at the front end of the housing 2, and is connected to the image forming path 4A. be. A plurality of circulation rollers 18 are provided in the reversing conveying section 12B. Further, a reversing path sensor 53 is provided in the reversing conveying section 12B. Based on the detection signal of the reversing path sensor 53, the control section 61 can detect the sheet P conveyed by the reversing conveying section 12B.

The flap 31 is arranged behind and above the fixing device 10 at a portion connecting the lower end portion of the discharge transport portion 5, the lower end portion of the switchback transport portion 12A, and the upper end portion of the reversing transport portion 12B. . The flap 31 has a plate shape extending in the vertical direction. The flap 31 is rotatable with its upper end as the center of rotation. The flap 31 can be switched between, for example, three rotational positions by the driving force of the motor M. As shown in FIG. The first position is a position where the switchback conveying section 12A is closed and the image forming conveying section 4 and the discharge conveying section 5 are connected, as indicated by the solid line in FIG. The second position is a position indicated by a chain double-dashed line in FIG. 1, in which the discharge transport section 5 is closed and the image forming transport section 4 and the switchback transport section 12A are connected. The third position is a position where the switchback conveying section 12A is closed and the discharge conveying section 5 and the reversing conveying section 12B are connected, as indicated by the dashed line in FIG. The control unit 61 can switch the connection of the transport unit 20 by controlling the motor M to switch the rotational position of the flap 31 .

The housing 2 has a guide portion 35 formed on a part of its upper surface. The guide portion 35 is arranged between the paper discharge port 2A and the passage port 2C in the front-rear direction, and is arranged between the paper discharge port 2A and the passage port 2C in the vertical direction. A flat surface parallel to the front-rear direction and the left-right direction is formed on the guide portion 35, and a plurality of ribs 35A are formed on the flat surface. Each of the plurality of ribs 35A protrudes upward from the flat surface and extends along the front-rear direction. Each of the plurality of ribs 35A is arranged at regular intervals in the left-right direction. When the guide portion 35 is viewed from above, the front end of the rib 35A is positioned so as to overlap the paper exit 2A. Further, the rear end of the rib 35A is positioned so as to overlap the passage port 2C.

(2. Control Configuration of MFP)
Next, the control configuration of the MFP 1 will be described with reference to FIG. As shown in FIG. 2, the MFP 1 includes a control section 61, a touch panel 63, hard keys 65, a FAX section 67, and a communication section 69 in addition to the image forming section 3 and the image reading section 13 described above. . The control unit 61 comprehensively controls each unit of the multifunction machine 1 . The units referred to here are the image forming unit 3, the image reading unit 13, and the like. The control unit 61 includes a CPU (central processing unit) 71 , a memory 73 and a RAM (random access memory) 75 .

The memory 73 is, for example, a non-volatile memory such as NVRAM. Note that the storage unit provided in the MFP 1 is not limited to the NVRAM memory, but may be a volatile RAM, ROM, HDD, an external storage device (such as a USB memory) connected to the MFP 1, or a storage unit combining them. But it's okay. Also, the storage unit may be a file server connected via a communication unit 69, which will be described later. Also, the storage unit may be a computer-readable storage medium. A computer-readable storage medium is a non-transitory medium. In addition to the above examples, non-transitory media include recording media such as CD-ROMs and DVD-ROMs. A non-transitory medium is also a tangible medium. On the other hand, an electrical signal that carries a program downloaded from a server on the Internet is a computer-readable signal medium, which is a kind of computer-readable medium, but is a non-transitory computer-readable storage. Not included in media.

The memory 73 stores various programs PG. The program PG is, for example, a program that controls each part of the multifunction machine 1 in a centralized manner. The RAM 75 is used as a storage area for temporarily storing data used when the CPU 71 executes the program PG, or as a work area for data processing. The CPU 71 executes the program PG and controls each part while temporarily storing the executed processing result in the RAM 75 . In the following description, the multi-function device 1 that executes the program PG by the CPU 71 may be simply referred to as a device name. For example, the statement “the control unit 61 of the multifunction device 1 executes printing by the image forming unit 3” is replaced with “the control unit 61 of the multifunction device 1 executes the program PG by the CPU 71 to control the image forming unit 3.” Therefore, it may mean that printing is executed by the image forming unit 3.

The touch panel 63 displays various information of the MFP 1 under the control of the control section 61 . Further, the touch panel 63 outputs to the control unit 61 a signal corresponding to the content of the operation received by the touch operation. The hard key 65 is a key formed by hardware. Typical examples thereof include a power switch and a reset switch (both not shown).

The communication unit 69 is, for example, a LAN (local area network) interface. The multifunction device 1 is connected to a LAN or WAN via the communication unit 69 and receives a job instructing printing or FAX from a PC or the like. The FAX unit 67 transmits and receives FAX data to and from another facsimile device via a telephone line. The FAX unit 67 transmits image data generated by the image reading unit 13 or image data of a job received from a PC connected to the communication unit 69, for example.

(3. Printing operation)
Next, the operation of single-sided printing by the multifunction machine 1 having the configuration described above will be described. More specifically, when the received print job is started, the control unit 61 of the multifunction machine 1 controls the exposure device 8 based on the image data set in the print job to irradiate the surface of the photosensitive drum 6 with the laser light L. and expose. Thereby, an electrostatic latent image based on the image data is formed on the surface of the photosensitive drum 6 . Next, the controller 61 controls the developing device 7 to supply toner to the electrostatic latent image on the surface of the photosensitive drum 6 by the developing roller 7A. Thereby, a toner image is carried on the surface of the photosensitive drum 6 .

Further, the control section 61 controls the image forming/conveying section 4 to supply the sheets P in the paper feeding tray 11 one by one at a predetermined timing to the image forming section 3 through the image forming path 4A. A sheet P is fed between the photosensitive drum 6 and the belt 9A. The belt 9</b>A conveys the sheet P from front to back so as to sequentially contact the four photosensitive drums 6 . The toner image on the surface of the photosensitive drum 6 is transferred to the sheet P when the sheet P and the photosensitive drum 6 come into contact with each other.

The fixing device 10 heats the sheet P bearing the toner image and sandwiches it between the heating roller 10A and the pressure roller 10B. The sheet P is heated and pressurized when passing between the heating roller 10A and the pressure roller 10B. Thereby, the fixing device 10 thermally fixes the toner image on the sheet P to the sheet P. FIG. The control unit 61 controls the ejection conveying unit 5 to eject the sheet P that has passed through the fixing device 10 from the ejection port 2A to the ejection tray 2B by the ejection rollers 15 .

Next, the operation of double-sided printing will be described.
The control unit 61 prints an image on one side of the sheet P in the same manner as the one-sided printing described above. The control section 61 moves the flap 31 to the second position (the position indicated by the two-dot chain line in FIG. 1) to connect the image forming conveying section 4 and the switchback conveying section 12A. The control unit 61 rotates the discharge roller 15 and the reversing roller 17, and guides the sheet P with one side printed from the fixing device 10 to the switchback conveying unit 12A. The control unit 61 controls the switchback conveying unit 12A to rotate the reversing roller 17 in the first rotation direction, and carries the sheet P into the switchback conveying unit 12A.

The sheet P is conveyed upward by the reversing rollers 17 . A portion of the sheet P on the downstream side in the conveying direction passes through the passage port 2C, is discharged onto the guide portion 35, and is conveyed forward along the ribs 35A. Further, the control section 61 rotates the stack lever 41 upward so that the rib 44 of the stack lever 41 is aligned with the rib 35A of the guide section 35 . The sheet P is conveyed forward along the rib 44 and the rib 35A.

The control unit 61 carries in the sheet P printed on one side to the switchback conveying unit 12A, and performs switchback for reversing the conveying direction, thereby switching the print surface. The control unit 61 of the present embodiment discharges a part of the sheet P from the passage port 2C when the switchback of the sheet P is performed by the switchback conveying unit 12A. By using a part of the upper surface of the housing 2 as a transfer path for switchback, the housing 2 can be made smaller.

Further, a plurality of ribs 35A extending in the front-rear direction are formed on the guide portion 35 of the present embodiment. A portion of the sheet P discharged from the passage port 2C is carried on the ribs 35A and 44. As shown in FIG. As a result, the contact area between the guide portion 35 and the stack lever 41 and the sheet P can be reduced, and the sheet P can be conveyed smoothly.

When the control unit 61 controls the switchback conveying unit 12A to convey the sheet P to a predetermined position, it reversely rotates the reversing roller 17 in the second rotation direction. Further, the control section 61 moves the flap 31 to the first position (solid line position in FIG. 1) to connect the switchback conveying section 12A and the reversing conveying section 12B. The sheet P is conveyed from the switchback conveying portion 12A to the reverse conveying portion 12B. The control unit 61 rotates the circulation roller 18 and the paper feed roller 16 to convey the sheet P to the image forming unit 3 again. For example, after an image is printed on the back surface (an example of the first surface), the sheet P is conveyed to the image forming unit 3 with the front surface (an example of the second surface) facing up. Here, the front side is, for example, the front printed side of the sheet P for which double-sided printing has been completed, and is the upper side when the sheet is stored in the paper feed tray 11 . The control unit 61 discharges the sheet P, which has been printed on both sides, from the discharge port 2A. Note that the control unit 61 may execute printing on the front side first, and then print on the back side. In this case, the surface is an example of the first aspect of the present application. The back surface is an example of a second surface.

(4. Types of double-sided printing)
In the double-sided printing described above, a method of executing double-sided printing for each sheet P (hereinafter sometimes referred to as a 21 method) has been described. In the 21 method, printing on the back side and printing on the front side are continuously performed for each sheet P from the start to the end of printing. For example, when receiving a print job for printing two sheets P1 and P2 in the 21 printing method, the control unit 61 performs printing in the following order.
Print the image of page 2 on the back side of the first sheet P1 Print the image of page 1 on the front side of the first sheet P1 and eject it Print the image of page 4 on the back side of the second sheet P2 Page 3 is printed on the front surface of the second sheet P2 and discharged. , the other sheet P2 is not printed.

In addition to the 21 methods described above, the control unit 61 of the present embodiment can perform double-sided printing of the sheets P in units of a plurality of sheets. Here, "performing double-sided printing of sheets P in units of a plurality of sheets" means "printing is performed on the first sides of each of the plurality of sheets P, and then printing is performed on the second sides of each of the plurality of sheets P ( The process of printing on the opposite side of the first side) is regarded as one cycle, and one or more cycles of processing are performed. The control unit 61 is capable of executing print processing of, for example, the 2413 method and the 246135 method as methods of double-sided printing in units of a plurality of sheets.

In the 2413 method, an operation of continuously printing on the back surfaces of the two sheets P1 and P2 and then continuously printing on the front surfaces of the sheets P1 and P2 is repeatedly executed. For example, when receiving a print job for printing two sheets P1 and P2 in the 2413 printing method, the control unit 61 performs printing in the following order.
The image of page 2 is printed on the back side of the first sheet P1 The image of page 4 is printed on the back side of the second sheet P2 The image of page 1 is printed on the front side of the first sheet P1 and ejected Page 3 image is printed on the surface of the second sheet P2 and ejected (the same printing process is repeated thereafter)

For example, in a state in which an image of 4 pages is printed and the sheet P2 is carried out from the image forming unit 3, the control unit 61 transfers the first sheet P1 having an image of 2 pages printed on the back side to the reverse conveying unit 12B. stay in In other words, two sheets P1 and P2 are present in the conveying section 20 of the multifunction machine 1 . This makes it possible to improve the throughput of double-sided printing.

Further, in the 246135 method, the operation of continuously printing on the back surfaces of the three sheets P1, P2, and P3 and then continuously printing on the front surfaces of the sheets P1, P2, and P3 is repeatedly executed. For example, when receiving a print job for printing three sheets P1, P2, and P3 in the 246135 printing method, the control unit 61 performs printing in the following order. In the following description, each group (number of copies) of sheets P1, P2, and P3 printed in units of three will be described as first copy, second copy, . . . in order of printing.
Print the image of page 2 of set 1 on the back side of the first sheet P1 Print the image of page 4 of set 1 on the back side of the second sheet P2 Print the image of page 6 of set 1 on the third sheet Print the 1st page image of the 1st set on the front side of the 1st sheet P1 and eject the 2nd page image of the 2nd set on the 1st sheet (fourth sheet in total) Print on the back side of P1 Print the image of page 3 of the first set on the front side of the second sheet P2 and eject the image of page 4 of the second set on the second sheet (5th sheet in total) Print on the back side Print the 5-page image of the first set on the front side of the third sheet P3 and eject it (the same printing process is repeated hereafter)

In the above-described 246135 method, three sheets P are present at maximum in the conveying section 20 of the multifunction machine 1 . FIG. 4 shows an example of a state in which three sheets P1 to P3 are present inside the conveying section 20. As shown in FIG. A sheet P1 shown in FIG. 4 is the first sheet on which two pages are printed on the back side. A sheet P2 indicates a second sheet on which an image of 4 pages is printed on the back side. Sheet P3 indicates the third sheet on which the image of page 6 is being printed on the back side.

The sheet P1 is switched back by the switchback conveying portion 12A and carried into the reversing conveying portion 12B. While the sheet P1 is conveyed through the reversing conveying portion 12B, the sheet P2 is conveyed upward in the switchback conveying portion 12A with its reverse side printed and conveyed to a position where it is guided by the ribs 35A and 44. The flap 31 is in the first position (the position indicated by the solid line in FIG. 2) and connects the switchback transport section 12A and the reverse transport section 12B. The sheet P2 is conveyed to the reverse conveying portion 12B by the reverse rotation of the reverse roller 17. FIG.

As time progresses from the state of the sheets P1 to P3 in FIG. 4, after the surface of the sheet P1 is printed, the sheet P1 passes through the discharge path 5A and the discharge port 2A, is discharged from the housing 2, and is transferred to the discharge tray 2B. loaded. After the sheet P1, the sheets P2 and P3 pass through the same conveying path as the sheet P1, and are stacked on the discharge tray 2B after being double-sided printed in order.

Note that the double-sided printing method and the positions of the sheets P1 to P3 described above are examples. For example, the control unit 61 may print four or more sheets P collectively. In this case, the control unit 61 may appropriately perform printing on the front side of the sheet P on which the back side has been printed before discharging the sheet. For example, the control unit 61 may execute a 2416385 method in which each page is printed in 2416385 order. In this case, the control unit 61 prints page 4 (the back side of the second sheet), prints page 1 (the front side of the first sheet), discharges the paper, and then prints page 6 (the back side of the third sheet). back side).

Further, the control unit 61 may perform control to switch back the sheet P within the discharge path 5A in addition to the switchback conveying unit 12A. That is, the control unit 61 may use two transport units, the discharge path 5A and the switchback transport unit 12A, for the sheet P switchback. As a result, double-sided printing can be executed at higher speed.

(5. Interrupt processing)
Here, the control unit 61 of this embodiment can execute interrupt processing. The interrupt processing referred to here means, for example, temporarily interrupting the job being executed while executing a job received by the touch panel 63 or a job received via the communication unit 69 and executing another job. processing. As an example, a case where copy processing is executed as interrupt processing will be described. For example, when the control unit 61 receives a print job from a PC via the communication unit 69 and receives a predetermined operation on the touch panel 63 while the print job is being executed, the screen shown in FIG. 3 is displayed on the touch panel 63. .

As shown in FIG. 3, the control section 61 displays an interrupt button 81 and a copy start button 83 . When the operation of touching the interrupt button 81 is accepted, the control unit 61 accepts copy settings and the like. When the control unit 61 accepts the operation of touching the copy start button 83 after accepting the copy settings, the control unit 61 suspends the job being executed and starts the execution of the copy job. The control unit 61 reads the image of the document set in the image reading unit 13 and prints the read image on the sheet P by the image forming unit 3 . After completing the copy process, which is an interrupt process, the control unit 61 resumes execution of the interrupted print job.

(6. Interrupt control)
Next, interrupt control when an interrupt process by the control unit 61 of this embodiment is received will be described with reference to FIGS. 5 and 6. FIG. 5 and 6 show the contents of interrupt control. For example, when the control unit 61 starts executing a print job instructing printing, the CPU 71 executes the program PG stored in the memory 73, and starts interrupt control shown in FIGS. It should be noted that the flowcharts of this specification basically show the processing of the CPU 71 according to the instructions described in the program PG. In other words, processing such as “judgment”, “interruption”, and “ejection” in the following description represents processing of the CPU 71 . Processing by the CPU 71 also includes hardware control.

Also, in the following description, the print job being executed first, that is, the interrupted print job may be referred to as the preceding job. Also, a job that is interrupted and executed may be called an interrupt job. Also, a case where a job for executing the above-described copy function is received as an interrupt job will be described.

As described above, the control unit 61 starts executing a print job, for example, when the interrupt control of FIGS. 5 and 6 is started. Then, when the control unit 61 starts interrupt control, in step 11 of FIG. 5 (hereinafter simply referred to as "S"), it determines whether or not the execution of the print job, which is the preceding job, has been completed. When the control unit 61 determines that the execution of the preceding job has not been completed (S11: NO), it determines whether or not an interrupt process has been received (S13).

For example, when receiving an operation on the copy start button 83 shown in FIG. 3, the control unit 61 determines that an interrupt process has been received (S13: YES). Note that the criterion for determining whether or not the interrupt process has been accepted is not limited to the operation of the copy start button 83 . For example, the control unit 61 may determine that an interrupt process has been accepted when an operation on the interrupt button 81 shown in FIG. 3 is accepted. Alternatively, the control unit 61 may determine that an interrupt process has been accepted when a high-priority job instructing an interrupt is accepted via the communication unit 69 .

The control unit 61 repeatedly executes the determination processes of S11 and S13 until the interrupt process is accepted (S13: NO). Further, when the control unit 61 determines that the execution of the preceding job is completed in S11 (S11: YES), the interrupt control shown in FIGS. 5 and 6 ends. Therefore, after starting execution of the preceding job, the control unit 61 does not accept interrupt processing (S13: NO), and when execution of the preceding job is completed (S11: YES), interrupt control ends.

If the control unit 61 makes an affirmative determination in S13 (S13: YES), it determines whether the preceding job being executed is a double-sided print job of "performing double-sided printing of sheets P in units of multiple sheets". (S15). Note that, in the following description, double-sided printing "performing double-sided printing of sheets P in units of a plurality of sheets" may be referred to as high-speed double-sided printing. As described above, the control unit 61 conveys a plurality of sheets P within the conveying unit 20 when executing double-sided printing of the 2413 method or the 246135 method. Therefore, when the preceding job is high-speed double-sided printing and the double-sided printing of the sheet P being conveyed is not completed, control such as keeping the sheet P in the conveying section 20 is required. Therefore, the control unit 61 determines in S13 whether or not the preceding job is high-speed double-sided printing, and changes the control contents based on the determination result.

When the control unit 61 determines that the preceding job is not a high-speed double-sided printing job (S15: NO), the sheet P of the preceding job is discharged (S17 in FIG. 6). In this case, the preceding job is a single-sided print job or a double-sided print job of the 21 method described above. If the preceding job is a single-sided printing job, the control unit 61 ejects the sheet P being printed from the paper ejection port 2A. In addition, in the 21-mode double-sided printing, only one sheet P is transported in the transport section 20 at the same time during printing, as in single-sided printing. Therefore, when the preceding job is a 21-method print job, the control unit 61 completes double-sided printing and ejects the sheet P from the paper ejection port 2A. As a result, the conveying section 20 enters a state in which the sheet P is not retained in any of the image forming conveying section 4, the discharge conveying section 5, the switchback conveying section 12A, and the reverse conveying section 12B. The control unit 61 can execute an interrupt job, convey the sheet P to any path in the conveying unit 20, and can execute single-sided printing or double-sided printing. When the preceding job is a 21-system print job and the interrupt job is a single-sided printing job, the control unit 61 causes the sheet P of the preceding job to stay in the reversing conveying unit 12B, and executes the interrupt job, as will be described later. may be executed.

After discharging the sheet P being printed, the control unit 61 interrupts execution of the preceding job (S17). The control unit 61 stops newly feeding the sheet P related to the preceding job at the start of the interruption. For example, when the controller 61 determines that the interrupt process has been received in S13 (S13: YES), the controller 61 controls the image forming/conveying unit 4 to stop feeding the sheet P by the paper feed roller 16 and start the preceding job. The new feeding of the sheet P is interrupted. The control unit 61 starts executing an interrupt job (single-sided copy or double-sided copy) (S19). When the execution of the interrupt job is started, the control unit 61 determines whether or not the execution of the interrupt job is completed (S21). The control unit 61 executes the determination process of S21 until the execution of the interrupt job is completed (S21: NO). When the execution of the interrupt job is completed (S21: YES), the control unit 61 resumes the execution of the interrupted preceding job (S23). As a result, the preceding job such as single-sided printing can be temporarily interrupted, and after the interruption job is executed, the preceding job can be restarted. The control unit 61 terminates the interrupt control in FIGS. 5 and 6, executes S11 again, and accepts the interrupt process.

On the other hand, when the control unit 61 determines in S15 of FIG. 5 that the preceding job is a high-speed double-sided printing job (S15: YES), it determines the number of print pages of the preceding job (S25). For example, when starting execution of the preceding job, the control unit 61 executes a predetermined program PG and uses the storage area of the RAM 75 to implement a software counter. The control unit 61 counts the number of printed pages of the preceding job using a software counter. Note that the method for measuring the number of printed pages is not limited to a method using software processing such as a software counter, but may be a method using hardware processing such as a flip-flop circuit, or a method using both of them.

In S25, the control unit 61 determines whether the number of pages being printed or already printed is the second page or the (final page N-1) page. Here, the “page being printed” is, for example, a page that is being prepared for printing by the image forming section 3 or a page that is being printed at the time when the determination in S13 is affirmative. Further, the “printed page” is, for example, a page on which printing has been completed on the sheet P that passed through the image forming section 3 immediately after the affirmative determination was made in S13. That is, it is the page that completed printing immediately before the interruption. Also, the “last page N−1” page is the page one page before the last page N when all printing of high-speed double-sided printing is completed. The final copy and the back side (page) of the final sheet P included in the final copy in the case of high-speed double-sided printing. FIG. 7 is a simplified illustration of the transport section 20 of the multifunction machine 1 shown in FIG. A mark enclosing a number in a square in FIG. 7 means that the image of the page of the number is printed on the side of the sheet P to which the number is attached. Also, a plurality of sheets P to be printed are illustrated as sheet P1, sheet P2, sheet P3, . . .

FIG. 7 shows a state in which two pages (number 2 surrounded by a square in the figure) are printed on the back side of the first sheet P1. The sheet P1 is printed on only one side (back side) of the double-sided printing. Therefore, when the number of pages being printed or printed is two in S25 (S25: YES), the control unit 61 controls the switchback conveying unit 12A and the like to switch back the sheet P1 as shown in FIG. It is conveyed into the conveying section 12A and retained in the switchback conveying section 12A (S27). Here, for example, the control unit 61 performs control for causing the sheet P1 to stay in the switchback conveying unit 12A according to the following procedure. After the time T1 from the passage of the edge of the sheet P1 (for example, the trailing edge or the upstream edge) of the sheet P1 through the branch sensor 50, the control unit 61 moves the sheet P1 while the sheet P1 is nipped by at least one of the reversing rollers 17. is stopped. This time T1 is, for example, slightly longer than the time from when the trailing edge (upstream edge) of the sheet passes the branch sensor 50 to when it passes the first reversing roller 17 . For example, the control unit 61 retains the sheet P1 in a state in which a portion of the sheet P1 on the downstream side is protruded from the passage port 2C. Therefore, based on the detection signal of the branch sensor 50 and the time T1, the control section 61 determines whether or not the sheet P1 has been retained in the switchback conveying section 12A. Alternatively, for example, after the branch sensor 50 detects the upstream end of the sheet P1, the control unit 61 stops the reversing roller 17 at the timing when the reversing roller 17 is rotated by a predetermined number of rotations. 8 may be stopped at a predetermined position. The control unit 61 suspends the preceding job while the sheet P1 remains in the switchback conveying unit 12A (S27). For example, the control unit 61 temporarily saves information such as the number of pages being printed and image data being processed for the preceding job in a predetermined area of the RAM 75, and interrupts the preceding job. As a result, as shown in FIG. 8, the sheet P in the image forming conveying section 4, discharge conveying section 5 and reversing conveying section 12B can be eliminated.

Further, when printing the "final page N-1" page on the back surface of the final sheet PN, as in FIG. . Therefore, if the controller 61 determines in S25 that the "last page N-1" page is being printed or has been printed on the back side of the last sheet PN (S25: YES), the sheet PN is printed in the same manner as the second page. The preceding job is interrupted by staying in the switchback conveying section 12A (S27).

As shown in FIG. 9, when the interrupt process is accepted at the stage where the sheet PN on which the "final page N-1" page is printed on the reverse side is conveyed to the reversing conveying unit 12B, the control unit 61 determines the type of the interrupt job. You may change control according to. As shown in FIG. 9, when the sheet PN stays in the reversing conveying section 12B, it becomes difficult to use the reversing conveying section 12B in an interrupt job. On the other hand, if the interrupt job is a single-sided print job, printing can be performed using only the image forming path 4A and the ejection path 5A. Therefore, for example, after starting control to discharge the sheet PN from the switchback conveying unit 12A, the control unit 61 receives an interrupt job, and if the interrupt job is double-sided printing, discharges the sheet PN, and reverses the sheet PN. The sheet P is removed from the transport section 12B (S27). The control unit 61 prints the final page N on the surface of the sheet PN and discharges it. As a result, the double-sided printing interrupt job can be properly executed using the reversing conveying section 12B.

Further, for example, after starting the control of discharging the sheet PN from the switchback conveying unit 12A, if an interrupt job is received and the interrupt job is single-sided printing, the control unit 61 transfers the sheet PN to the reverse conveying unit 12B. Stay (S27). Here, for example, the control unit 61 performs control for causing the sheet PN to stay in the reversing conveying unit 12B according to the following procedure. After the time T2 after the edge of the sheet PN (e.g., leading edge, downstream edge) passes the reversing path sensor 53, the control unit 61 detects the sheet PN while the sheet PN is nipped by at least one of the circulation rollers 18. is stopped. This time T2 is, for example, the time from when the leading edge of the sheet passes the reversing path sensor 53 to when it passes the final circulation roller 18 on the downstream side. As shown in FIG. 9, for example, the control unit 61 causes the sheet PN to stay at a position detectable by the reversing path sensor 53, and interrupts the preceding job. As a result, the single-sided printing interrupt job can be properly executed only in the image forming path 4A and the discharge path 5A.

After executing S27, the control unit 61 determines whether or not the interrupt job is double-sided printing (S29 in FIG. 6). When the control unit 61 determines that the interrupt job is not double-sided printing, that is, single-sided printing (S29: NO), it starts a single-sided printing interrupt job (S31). In this case, for example, in the state of FIG. 8, the control unit 61 executes the interrupt job (single-sided printing) while the sheet P1 remains in the switchback conveying unit 12A. Further, in the state of FIG. 9, the control unit 61 executes an interrupt job (single-sided printing) with the sheet PN staying in the reversing conveying unit 12B. After executing S31, the control unit 61 determines completion of the interrupt job (S21), and when completing the interrupt job, resumes the interrupted preceding job (S23).

Further, in S29, when the control unit 61 determines that the interrupt job is double-sided printing (S29: YES), the interrupt job of double-sided printing is started (S32). In this case, the control unit 61 switches back the sheet P in the discharge conveying unit 5 . FIG. 10 shows a state in which switchback is performed in the discharging/conveying section 5. As shown in FIG. In the example shown in FIG. 10, the control unit 61 causes the sheet PW1 of the interrupt job to be switched back to the discharge path 5A while the sheet P1 is retained in the switchback conveying unit 12A. For example, the control unit 61 conveys the sheet PW1 from the paper feed tray 11 to the image forming unit 3, prints an image on the back surface of the sheet PW1, and then conveys the sheet PW1 to the ejection path 5A. At this time, the control unit 61 sets the flap 31 to the first position (the position indicated by the solid line in FIG. 1). After conveying the sheet PW1 to a predetermined position on the discharge path 5A, the control unit 61 stops the sheet discharge rollers 15 to stop the sheet PW1. For example, the control unit 61 stops the sheet PW1 at a position where the downstream end of the sheet PW1 is out of the discharge port 2A. The control section 61 rotates the flap 31 to the third position (the position indicated by the dashed line in FIG. 1) to connect the discharging conveying section 5 and the reversing conveying section 12B. Then, the control unit 61 conveys the sheet PW1 to the image forming unit 3 by the reversing conveying unit 12B, prints the front surface, and discharges the sheet from the discharge port 2A. Note that the control unit 61 may execute double-sided printing by conveying two sheets P according to the 2413 method in executing the interrupt job. After executing S32, the control unit 61 executes the processes after S21.

On the other hand, if a negative determination is made in S25 of FIG. 5 (S25: NO), the control unit 61 determines whether the page being printed or printed is the last page N (S33). A state in which the final page N is being printed or has been printed means a state in which the sheet PN is further conveyed into the image forming path 4A from the state shown in FIG. If the control unit 61 makes an affirmative determination in S33 (S33: YES), and the final page N is being printed, the control unit 61 completes the printing of the final page N and discharges the sheet PN (S35). Further, if the printing of the final page N is completed, the control section 61 discharges the final sheet PN from the passage port 2C (S35). The control unit 61 starts the interrupt job (S37), and executes the processes after S21 in FIG. As a result, the sheet P can be removed from the conveying section 20 and the interrupt job can be started.

If a negative determination is made in S33 (S33: NO), the number of pages being printed or already printed will be less than (final page N-1) after the fourth page. Note that in high-speed double-sided printing (2413 method, 246135 method, etc.), as described above, after printing two pages, page four is printed. Therefore, the printing range of page 4 onwards and less than (last page N-1) includes printing of page 1 and page 3. FIG.

If a negative determination is made in S33 (S33: NO), the control unit 61 retains the preceding sheet on which printing was performed earlier among the unprinted sheets P in the reversing conveying unit 12B. Further, the control unit 61 causes the succeeding sheet to be printed later among the unprinted sheets P to stay in the switchback conveying unit 12A (S39). Further, if three or more sheets are being conveyed, the control section 61 completes printing until only two sheets P remain (S39). Then, the control unit 61 suspends the preceding job being executed (S39). Specific examples will be described below with reference to FIGS. 11 to 14. FIG. FIGS. 11, 13, and 14 show the state at the time when an affirmative determination is made in S13 (S13: YES), that is, when the interrupt process is accepted.

FIG. 11 shows a state in which 4 pages are printed on the back side of the second sheet P2. In the state shown in FIG. 11, the first sheet P1 on which two pages have been printed is conveyed, for example, by the reversing conveying section 12B. In this case, sheet P1 is the preceding sheet. Sheet P2 is a subsequent sheet. As shown in FIG. 12, the control unit 61 causes the sheet P1 to stay in the reversing conveying unit 12B and causes the sheet P2 to stay in the switchback conveying unit 12A. That is, the two sheets P1 and P2 are retained in the conveying section 20. FIG. As a result, the sheet P can be removed from the image forming path 4A and the discharge path 5A.

FIG. 13 shows a state in which 6 pages are printed on the back side of the third sheet P3 in the 246135 method. In the state shown in FIG. 13, the sheet P2 on which 4 pages have been printed is conveyed by the switchback conveying section 12A. The first sheet P1 on which two pages have been printed is conveyed by the reversing conveying section 12B. Thus, FIG. 13 is slightly later than the situation shown in FIG. In this case, when the control unit 61 detects that the three sheets P1, P2, and P3 are being conveyed based on the detection signal of the branch sensor 50 or the like, the printing of the first sheet P1 is completed and discharged. The preceding sheet P1 referred to here is the sheet P1 that has started printing earliest among the three sheets P1, P2, and P3, in other words, the sheet P1 that has been supplied from the paper feed tray 11 earliest. is. The control unit 61 prints the first page on the surface of the sheet P1 and discharges it. 12, the control unit 61 causes the second sheet P2 to stay in the reversing conveying unit 12B and causes the third sheet P3 to stay in the switchback conveying unit 12A.

FIG. 14 shows a state in which one page is printed on the front side of the first sheet P1 by the 246135 method. In the state shown in FIG. 14, the sheet P2 on which 4 pages have been printed is conveyed by the reversing conveying section 12B. A third sheet P3 on which 6 pages have been printed is conveyed by the switchback conveying section 12A. Further, the controller 61 carries the fourth sheet P4 from the paper feed tray 11 to the image forming path 4A. When the control unit 61 detects that the four sheets P1 to P4 are being conveyed based on the detection signal of the branch sensor 50 or the like, the control unit 61 shifts the first sheet P so that the number of sheets P in the conveying unit 20 is two. The second sheet P1 and the second sheet P2 are completely printed and discharged. Therefore, when there are a plurality of sheets P in the transport unit 20 , the control unit 61 prints the sheets in order from the one with the earliest print order (the one with the smallest page number) until two sheets P remain in the transport unit 20 . Complete printing and eject. As in FIG. 12, the control unit 61 causes the third sheet P3 to stay in the reversing conveying unit 12B and causes the fourth sheet P4 (back side printed) to stay in the switchback conveying unit 12A. In this manner, the control unit 61 causes each of the two sheets P shown in FIG. 12 to stay in the switchback conveying unit 12A and the reverse conveying unit 12B.

As described above, the control unit 61 of the present embodiment can use the reversing conveying unit 12B while the sheet P is retained in the switchback conveying unit 12A, and can execute not only single-sided printing but also double-sided printing interrupt jobs. can. Further, the control unit 61 can execute a single-sided printing interruption job in a state in which one sheet P is accumulated in each of the switchback conveying unit 12A and the reversing conveying unit 12B. In other words, the control unit 61 is not limited to the high-speed double-sided printing method (type) described above, and can use the switchback conveying unit 12A and the reversing conveying unit 12B as the conveying unit 20 in which the sheet P is retained. , interrupt processing can be executed.

After executing S39, the control unit 61 determines whether or not the interrupt job is a double-sided print job (S41). When the control unit 61 determines that the interrupt job is a double-sided print job (S41: YES), it executes S43 of FIG. As shown in FIG. 12, in the state where S39 is executed, the sheet P of the preceding job is retained in the reversing conveying section 12B. In order to execute the double-sided printing interrupt job, the control unit 61 completes the printing of the sheet P of the reversing/conveying unit 12B and starts the process of discharging the sheet (S43). After executing S43, the control unit 61 determines whether or not the sheet P staying in the reversing conveying unit 12B has been discharged to the discharge tray 2B (an example of the predetermined position) (S45). The control unit 61 can determine whether the sheet P has been discharged based on the detection signal of the paper discharge sensor 52 .

The control unit 61 continues the ejection process until the ejection of the sheet P is completed (S45: NO). When the discharge of the sheet P is completed (S45: YES), the control unit 61 switches back the sheet P of the interruption job by the discharge conveying unit 5 while the sheet P is retained in the switchback conveying unit 12A. The interrupt job is executed (S32, see FIG. 10). Note that the timing at which the control unit 61 starts executing S32 is not limited to the timing at which the discharge of the sheet P from the reversing conveying unit 12B is completed (S45: YES). That is, the predetermined position in the determination process of the present application is not limited to the discharge tray 2B, and may be a position passing through the branch sensor 50, for example. In this case, the control unit 61 may cause the image forming unit 3 to complete the printing of the sheet P of the reverse conveying unit 12B, and start S32 in response to the detection of the completed sheet P by the branch sensor 50. good.

If the control unit 61 makes a negative determination in S41 (S41: NO), that is, if the interrupt job is a single-sided print job, the control unit 61 causes the sheet P to stay in each of the switchback conveying unit 12A and the reverse conveying unit 12B. In this state, an interrupt job of single-sided printing is executed (S31). After executing S31 or S32, the control unit 61 executes the processes after S21. In this manner, the MFP 1 of the present embodiment can cause the sheet P of the preceding job to stay in the switchback conveying section 12A or the reversing conveying section 12B, and can quickly start an interrupt job.

As described above, according to the above-described embodiment, the following effects are obtained.
(1) The multifunction machine 1 of the present embodiment includes a discharge tray 2B, an image forming/conveying unit 4 that conveys the sheet P to the image forming position, and a discharge conveying unit that discharges the sheet P that has passed the image forming position to the discharge tray 2B. 5 and a re-conveying unit 12 for reconveying the sheet P reversed after passing the image forming position to the image forming position, and forming an image on the sheet P conveyed to the image forming position. An image forming section 3 and a control section 61 are provided. Upon receiving a double-sided image forming job, the control unit 61 controls the conveying unit 20 and the image forming unit 3 to form an image on the back surface (an example of the first surface) of each of the plurality of sheets P, and then A process of forming an image on each surface (an example of the second surface) of the sheet P is regarded as one cycle, and a process (an example of a double-sided image forming process and a double-sided image forming process) is executed for one or more cycles. . If an interrupt job (an example of an interrupt image forming job) is received during execution of a preceding job (an example of a double-sided image forming job) (S13: YES), the control unit 61 controls the image forming unit 3 to perform the preceding job. (an example of an interruption process and an interruption process) for interrupting the operation of the image forming unit 3 according to the above, and by controlling the conveying unit 20 to cause the sheet P existing in the conveying unit 20 to stay in the re-conveying unit 12. In the processing of S27 and S39 (an example of a staying process and a staying step) to cause the sheet P to remain in the re-conveying section 12, the conveying section 20 and the image forming section 3 are controlled to generate an image related to the interrupt job. are formed on the sheet P (an example of an interrupt image forming process, an interrupt image forming process) of S29, S31, S32, and S41.

According to this, if an interrupt job is received during execution of a preceding job of printing a plurality of sheets P together one side at a time, the control section 61 interrupts the operation of the image forming section 3 related to the preceding job. The control unit 61 causes the sheet P existing in the conveying unit 20 to stay in the re-conveying unit 12 . Then, the control unit 61 controls the conveying unit 20 and the image forming unit 3 to print the image related to the interrupt job on the sheet P while the sheet P remains in the re-conveying unit 12 . The conveying unit 20 has a re-conveying unit 12 for conveying the reversed sheet P, in addition to the discharge conveying unit 5 for discharging the printed sheet P. As shown in FIG. Therefore, by causing the sheets P of the preceding job to stay in the re-conveying section 12, the sheets P in the image forming conveying section 4 and the discharge conveying section 5 can be eliminated. The control unit 61 can start an interrupt job and start printing on a new sheet PW1 while the sheet P of the preceding job is held. Therefore, when an interrupt request for a new job is made during double-sided printing of a sheet, it is possible to advance the start of printing related to the interrupt job.

(2) The re-conveying unit 12 also includes a switchback conveying unit 12A that switches back the sheet P that has passed through the image forming position, and conveys the sheet P that has been switched back by the switchback conveying unit 12A to the image forming conveying unit 4. and a reversing conveying unit 12B. When the control unit 61 determines that the interrupt job is a job to print on both sides of the sheet P and determines that the sheet P is staying in the reversing conveying unit 12B (S41: YES, S45: NO), The processing of S45 (an example of standby processing) for waiting for the execution of the interrupt job is executed.

When the sheet P remains in the reversing conveying portion 12B, it becomes difficult to re-convey the reversed sheet P to the image forming position, and thus it becomes difficult to execute the interrupt forming job for printing on both sides of the sheet. For this reason, when the sheets P are stagnant in the reversing conveying section 12B, waiting for the execution of the succeeding interrupt job causes collision between the preceding sheet P and the succeeding sheet P in the reversing conveying section 12B. can be suppressed.

(3) Further, the control unit 61 performs the processing of S45 (an example of the determination processing) for determining whether or not the sheet P staying in the reversing transport unit 12B has been transported to the discharge tray 2B (an example of the predetermined position). Execute. If the control section 61 makes an affirmative determination in the process of S45 (S45: YES), it starts executing the interrupt job (S32). According to this, when the sheet P remains in the reversing conveying section 12B and an interrupt job for printing on both sides of the sheet is received, the interrupt job is executed after conveying the sheet P from the reversing conveying section 12B to the discharge tray 2B. Start. As a result, it is possible to reliably eliminate the sheet P from the reversing conveying section 12B and appropriately execute an interrupt job for printing on both sides of the sheet.

(4) In addition, when the control unit 61 determines that the interrupt job is a job that prints only on one side of the sheet P and determines that the sheet P is staying in the reversing conveying unit 12B (S27, S29 : NO, S39, S41: NO), the interrupt job is executed while the sheet P remains in the reversing conveying section 12B (S31). The switchback conveying section 12A and the reversing conveying section 12B are provided separately from the image forming conveying section 4 and the discharge conveying section 5 . Therefore, even if the sheet P is stagnant in the reversing conveying portion 12B, the image forming conveying portion 4 and the discharge conveying portion 5 can be used to execute an interrupt job for printing only on one side of the sheet. can. As a result, single-sided printing can be interrupted and executed while the sheet is retained in the reversing conveying unit 12B, and FPOT (abbreviation for First Print Out Time) can be shortened.

(5) Further, the control unit 61 determines that the interrupt job is a job that prints only on one side of the sheet P, and the sheet P remains in each of the switchback conveying unit 12A and the reverse conveying unit 12B. If it is determined (S39, S41: NO), the interrupt job is executed while the sheets P are retained in each of the switchback conveying portion 12A and the reversing conveying portion 12B (S31). According to this, even when sheets P are stagnant in both the switchback conveying portion 12A and the reversing conveying portion 12B, the image forming conveying portion 4 and the discharge conveying portion 5 are used for an interrupt job of single-sided printing. can be performed using

(6) Further, when receiving an interrupt job during execution of the preceding job, the control section 61 controls the image forming section 3 to transfer the sheet P conveyed to the image forming position in the image forming conveying section 4. Upon completion of printing, the operation of the image forming section 3 relating to the preceding job is interrupted (for example, the states of FIGS. 14 to 12). According to this, the interrupt job can be started after the printing of the sheet P being conveyed to the image forming position is completed.

(7) Further, the re-conveying section 12 has a switchback conveying section 12A that switches back the sheet P that has passed through the image forming position. The control unit 61 causes the sheet P being conveyed to stay in the switchback conveying unit 12A (FIGS. 8, 10, and 12). As a result, printing can be interrupted while the sheet P remains in the switchback conveying unit 12A, and the FPOT can be shortened.

(8) Further, when the control unit 61 determines that the interrupt job is a job to print on both sides of the sheet P and determines that the sheet P is staying in the switchback conveying unit 12A (S29: YES ), in the execution of the interrupt job, the conveying unit 20 is controlled to switch back the sheet P in the discharge conveying unit 5 (S32, FIG. 10). When the sheet P is accumulated in the switchback conveying portion 12A, switchback by the switchback conveying portion 12A becomes difficult. Therefore, by executing the switchback in the discharging/conveying section 5, it is possible to appropriately execute even the interrupt job of double-sided printing.

Note that the content of the present application is not limited to the above-described embodiments, and various modifications can be made without departing from the spirit of the present application.
For example, the control unit 61 may start executing the interrupt job while discharging the sheet P of the preceding job from the reverse conveying unit 12B. That is, the interrupt job may be started in a state in which the sheets P are accumulated in the reversing conveying section 12B, and printing may be performed so that the sheets P do not collide with each other.
Further, the control unit 61 collectively executes the interruption processing of interrupting the operation of the image forming unit 3 and the retention processing of causing the sheet to remain in the re-conveying unit 12 in S27 or S39. can be run separately. In this case, the control unit may first execute the interruption process and then execute the stay process, or conversely, may execute the stay process first and then execute the interruption process.

In the above embodiment, a color multifunction machine is used as the image forming apparatus of the present application. Alternatively, the image forming apparatus may be a copier having only a copying function or a printer having only a printing function.
Further, although the image forming section 3 prints an image on the sheet P using an electrophotographic method, it may form an image on the sheet P using another image forming method such as an inkjet recording method.

1 MFP 2B Discharge Tray 3 Image Forming Section 4 Image Forming Conveying Section 5 Ejecting Conveying Section 12 Reconveying Section 12A Switchback Conveying Section 12B Reverse Conveying Section 20 Conveying Section 61 Control Section P, P1-P4, PW1 sheet.

Claims (6)

a discharge tray, an image forming conveying section for conveying a sheet to an image forming position, a discharging conveying section for discharging the sheet that has passed through the image forming position to the discharge tray, and a switchback for the sheet that has passed through the image forming position. a conveying unit having a switchback conveying unit and a reversing conveying unit that conveys the sheet switched back by the switchback conveying unit to the image forming conveying unit;
an image forming unit that forms an image on the sheet conveyed to the image forming position;
a control unit;
a first position where the switchback transport section is closed and the image forming transport section and the discharge transport section are connected; and a second position where the discharge transport section is closed and the image formation transport section and the switchback transport section are connected. and a third position that closes the switchback conveying section and connects the discharge conveying section and the reversing conveying section under the control of the control section. and,
with
Upon receiving a double-sided image forming job, the control unit controls the conveying unit and the image forming unit to form an image on the first surface of each of the plurality of sheets, and An image forming apparatus that performs double-sided image forming processing in which processing for forming an image on a second surface is set as one cycle, and the processing is performed in one or more cycles,
The control unit
When an interrupt image forming job is accepted during execution of the double-sided image forming process,
an interruption process of controlling the image forming section to interrupt the operation of the image forming section relating to the double-sided image forming process;
When the interrupt image forming job is a job for forming images on the first side and the second side of a sheet, the flap is set at the second position to connect the image forming conveying section and the switchback conveying section, and a retention process of controlling a conveying unit to cause the sheet existing in the conveying unit to remain in the switchback conveying unit ;
In a state where the sheet is stagnant in the switchback conveying section , the image forming conveying section, the image forming section, the discharge conveying section, and the reverse conveying section are controlled to transfer the image related to the interrupt image forming job to the sheet. wherein the flap is positioned at the first position, the image forming/conveying section and the discharging/conveying section are connected, and after the sheet that has passed through the image forming position is conveyed to the discharging/conveying section, The flap is set to the third position to connect the discharging conveying portion and the reversing conveying portion, the switchback conveying portion is closed by the flap, and the entire sheet retained in the switchback conveying portion is conveyed in the switchback manner. an interrupt image forming process for controlling the sheet conveyed to the discharging conveying unit while being accommodated in the unit so that the sheet is switched back and conveyed to the reverse conveying unit;
An image forming apparatus that executes The control unit
when determining that the interrupt image forming job is an interrupt image forming job that forms an image only on the first surface of the sheet;
in the staying process, controlling the conveying unit so that the sheet existing in the conveying unit is accumulated in the reverse conveying unit;
controlling the image forming and conveying unit, the image forming unit, the discharging conveying unit, and the reversing conveying unit in the interrupt image forming process to form an image related to the interrupt image forming job on a sheet;
2. The image forming apparatus according to claim 1, wherein: The control unit
when determining that the interrupt image forming job is an interrupt image forming job that forms an image only on the first surface of the sheet;
In the staying process, controlling the conveying unit so that two sheets present in the conveying unit are accumulated in the switchback conveying unit and the reverse conveying unit, respectively;
controlling the image forming and conveying unit, the image forming unit, the discharging conveying unit, and the reversing conveying unit in the interrupt image forming process to form an image related to the interrupt image forming job on a sheet;
2. The image forming apparatus according to claim 1, wherein: The control unit
In the interrupting process, when an interrupt image forming job is accepted during execution of the double-sided image forming process, the image forming unit is controlled to transfer a sheet conveyed to the image forming position in the image forming conveying unit. 4. The image forming apparatus according to any one of claims 1 to 3 , wherein the operation of said image forming section relating to said double-sided image forming process is interrupted in response to completion of image forming. a discharge tray, an image forming conveying section for conveying a sheet to an image forming position, a discharging conveying section for discharging the sheet that has passed through the image forming position to the discharge tray, and a switchback for the sheet that has passed through the image forming position. a conveying unit having a switchback conveying unit and a reverse conveying unit for conveying the sheet switched back by the switchback conveying unit to the image forming conveying unit; and forming an image on the sheet conveyed to the image forming position. a control unit; a first position at which the switchback conveying unit is closed and the image forming conveying unit and the discharge conveying unit are connected; a second position connecting the switchback conveying section; and a third position closing the switchback conveying section and connecting the discharging conveying section and the reversing conveying section. A flap that rotates under the control of a control unit, and an image forming method in an image forming apparatus comprising:
When a double-sided image forming job is received, the conveying unit and the image forming unit are controlled to form an image on the first side of each of the plurality of sheets, and then to form the image on the second side of each of the plurality of sheets. A double-sided image forming step in which the processing for forming the
When an interrupt image forming job is received during execution of the double-sided image forming process,
a suspending step of controlling the image forming unit to suspend the operation of the image forming unit relating to the double-sided image forming step;
When the interrupt image forming job is a job for forming images on the first side and the second side of a sheet, the flap is set at the second position to connect the image forming conveying section and the switchback conveying section, and a staying step of controlling a conveying unit to cause the sheet existing in the conveying unit to stay in the switchback conveying unit ;
In a state where the sheet is stagnant in the switchback conveying section , the image forming conveying section, the image forming section, the discharge conveying section, and the reverse conveying section are controlled to transfer the image related to the interrupt image forming job to the sheet. wherein the flap is positioned at the first position, the image forming/conveying section and the discharging/conveying section are connected, and after the sheet that has passed through the image forming position is conveyed to the discharging/conveying section, The flap is set to the third position to connect the discharging conveying portion and the reversing conveying portion, the switchback conveying portion is closed by the flap, and the entire sheet retained in the switchback conveying portion is conveyed in the switchback manner. an interrupt image forming step of controlling to switch back the sheet conveyed to the discharging conveying portion while being accommodated in the section and conveying the sheet to the reversing conveying portion;
An imaging method, comprising: a discharge tray, an image forming conveying section for conveying a sheet to an image forming position, a discharging conveying section for discharging the sheet that has passed through the image forming position to the discharge tray, and a switchback for the sheet that has passed through the image forming position. a conveying unit having a switchback conveying unit and a reverse conveying unit for conveying the sheet switched back by the switchback conveying unit to the image forming conveying unit; and forming an image on the sheet conveyed to the image forming position. a first position at which the switchback conveying section is closed and the image forming conveying section and the discharging conveying section are connected; and at which the discharging conveying section is closed and the image forming conveying section and the switchback conveying section are closed. and a third position that closes the switchback transport and connects the discharge transport and the reversing transport. A program for causing a computer to control an image forming apparatus comprising:
to the computer;
When a double-sided image forming job is received, the conveying unit and the image forming unit are controlled to form an image on the first side of each of the plurality of sheets, and then to form the image on the second side of each of the plurality of sheets. A two-sided image forming process for performing one or more cycles of the process of forming the
When an interrupt image forming job is accepted during execution of the double-sided image forming process,
an interruption process of controlling the image forming section to interrupt the operation of the image forming section relating to the double-sided image forming process;
When the interrupt image forming job is a job for forming images on the first side and the second side of a sheet, the flap is set at the second position to connect the image forming conveying section and the switchback conveying section, and a retention process of controlling a conveying unit to cause the sheet existing in the conveying unit to remain in the switchback conveying unit ;
In a state where the sheet is stagnant in the switchback conveying section , the image forming conveying section, the image forming section, the discharge conveying section, and the reverse conveying section are controlled to transfer the image related to the interrupt image forming job to the sheet. wherein the flap is positioned at the first position, the image forming/conveying section and the discharging/conveying section are connected, and after the sheet that has passed through the image forming position is conveyed to the discharging/conveying section, The flap is set to the third position to connect the discharging conveying portion and the reversing conveying portion, the switchback conveying portion is closed by the flap, and the entire sheet retained in the switchback conveying portion is conveyed in the switchback manner. an interrupt image forming process for controlling the sheet conveyed to the discharging conveying unit while being accommodated in the unit so that the sheet is switched back and conveyed to the reverse conveying unit;
The program that causes the to run.

Images